The present invention relates to a device for feeding working fluid to an assembly requiring working fluid, including at least one fluid channel extending from a surface, and at least one screw element capable of being screwed from the surface into the at least one fluid channel for feeding working fluid into the fluid channel or to close the fluid channel.
The at least one fluid channel includes a first section directly adjacent to the surface having a larger width, a second section having a smaller width and, between the first section and the second section, a first transition region with an annular surface. The screw element includes at least one sealing surface capable of being brought into sealing engagement with the annular surface.
Working fluid feeding devices of this type are used, e.g., on the end faces of guide carriages of linear guide devices, the end faces of screw nuts of rolling element screw drives or similar devices based on rolling-contact bearing technology. The working fluid used is a lubricant, e.g., a lubricating grease or lubricating oil, e.g., in the form of oil-air or oil-mist lubrication. With regard for the related art, reference is made, e.g., to publication DE 198 30 140 A1.
An attachment capable of being attached to the assembly is provided with the known working fluid feeding device, the attachment including a total of four working fluid feed holes. The upper feed hole is provided for the case in which the guide carriage is installed underneath a table board and working fluid, e.g., lubricant, must be fed through the table board. The other three fluid channels are typically used to receive screw elements, e.g., stoppers, or elements for connecting a working fluid reservoir. With the known working fluid feeding device, problems with the seal integrity of the fluid channels occur repeatedly in practice, even when screw elements are used that cut the associated counterthread themselves in the attachment with the fluid channel.
Publication US 2003/0160450 A1 makes known a screwed connection for tubular parts, with which a cylindrical screw element has a front side on which an annular ridge is formed. In the screwed-in state, the annular ridge penetrates the material at the base of a cylindrical counternut and displaces it into a groove formed between the front side of the screw element and the base surface of the nut. In the screwed-in state, this results in a labyrinth-type seal. The disadvantage, however, is that an adequate seal can be ensured only the first time the screw element is screwed in.
Publication DE 8320655 U1 makes known a threaded pipe coupling for connecting pipes, with which an inner flange of the coupling has a circumferential sealing ridge on its axial end faces that deform plastically when the front edges of a screwed-in pipe are tightened, thereby creating a seal.
Systems also exist with which the seal between the screw element and the nut element is attained using a deformable element supported between two sealing surfaces, e.g., a rubber ring. Reference is made to publication U.S. Pat. No. 1,889,689 for example purposes only.